1. Field of the Invention
The invention relates to adjustable shelf support systems in general, and more particularly to shelf support systems employing slotted shelf support strips.
2. Prior Art
A common adjustable shelving design in the prior art utilizes a design disclosed in U.S. Pat. No. 4,070,803 to Gartung, which is hereby incorporated by reference. This shelving system consists essentially of two or more vertical support strips containing a plurality of vertically aligned slots. Shelf support brackets having hooks designed to engage the slots in the support strips are attached to the strips. By positioning two or more strips parallel to each other on a wall, and aligning two or more brackets horizontally on the strips, the brackets can be used to support shelving. This type of shelving system provides a significant advantage over the prior art in that it may be installed over walls without requiring any alterations to the wall itself. However, the Gartung type shelving also have a significant shortcoming: stability. The hooks securing the brackets to the strips are much shorter than the brackets themselves. Force exerted against the shelves can use the full length of the brackets to exert leverage against the hooks. For this reason, small lateral forces can cause the brackets and the shelves they support to sway substantially. Gartung type shelving system also have vertical stability problems. The shelves are typically held on the brackets by their own weight. This can create problems if the shelf becomes unevenly laden. Consider a shelf supporting a collection of valuable but fragile lamps on one end and a bronze sculpture on the other. Lifting the sculpture during household cleaning may cause the shelf to become unbalanced and allow it to pivot on the bracket, and may lead to a tumble for the lamps. The shelves are also quite susceptible to displacement from upward forces. A shelf struck from below with a heavy object such as a dictionary being moved on a lower shelf may move upward with nothing but gravity to oppose it. If the bracket itself is bumped from below, it may be displaced and possibly even knocked out of the strip. Previous works, such as U.S. Pat. No. 5,253,835 to Herron which is hereby incorporated by reference in its entirety, have made substantial improvements to the horizontal stability of the shelving; however, problems persist in the state of the art with respect to the vertical stability of Gartung type shelving. Therefore, a shelving system satisfying the following objectives is desired.